3,942 research outputs found

    A Compiler for the dependently typed language Beluga

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    Les structures avec des lieurs sont très communes en informatique. Les langages de programmation et les systèmes logiques sont des exemples de structures avec des lieurs. La manipulation de lieurs est délicate, de sorte que l’écriture de programmes qui ma- nipulent ces structures tirerait profit d’un soutien spécifique pour les lieurs. L’environ- nement de programmation Beluga est un exemple d’un tel système. Nous développons et présentons ici un compilateur pour ce système. Parmi les programmes pour lesquels Beluga est spécialement bien adapté, plusieurs peuvent bénéficier d’un compilateur. Par exemple, les programmes pour valider les types (les "type-checkers"), les compilateurs et les interpréteurs tirent profit du soutien spécifique des lieurs et des types dépendants présents dans le langage. Ils nécessitent tous également une exécution efficace, que l’on propose d’obtenir par le biais d’un compilateur. Le but de ce travail est de présenter un nouveau compilateur pour Beluga, qui emploie une représentation interne polyvalente et permet de partager du code entre plusieurs back-ends. Une contribution notable est la compilation du filtrage de Beluga, qui est particulièrement puissante dans ce langage.In computer science, structures with variable binders are very common. Program- ming languages and logical frameworks are examples of structures with binders. Thus writing programs that deal with these kinds of data benefits with explicit support for data binding. The Beluga programming environment is an example of such a system. In this work we develop and present a compiler for the system. Many of the programs that Beluga is specially well suited for writing can benefit from a compiler. For example, some of the kinds programs that would benefit more are type-checkers, compilers and interpreters that take advantage of the binder support and dependent types present in the language, and also require a reasonably fast run-time. Our goal in this work, is to present a compiler for the Beluga system, that uses a very versatile internal representation that helps with the development of the system, and allows a sharing of code between several back-ends. Furthermore, we present a way of compiling the uniquely powerful pattern language supported by Beluga

    Meanings Expressed by Primary Schoolchildren When Solving a Partitioning Task

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    This research was funding from Junta de Andalucia Research Group FQM-193 on numerical and algebraic thinking.This study entailed an in-depth exploration of the meanings identified by a group of 105 fourth year primary schoolchildren when solving a task involving partitioning. The research was based on a semantic triangle consisting of a conceptual structure, representation systems, and sense. The content of children’s answers was analysed qualitatively. One of the most prominent findings was that purposes or usages were recognised based on multiple strategies, new categories of which, not envisaged in earlier research, were defined. Most of the students deployed graphic, verbal, and numerical representation and established relationships among them. Concepts such as the part-whole relationship and fractioning appeared in their description of conceptual structure, although errors were detected in terms of inequities and confusion between numerator and denominator.Junta de Andalucia FQM-19

    Thermal Performance of Facades Based on Experimental Monitoring of Outdoor Test Cells in Tropical Climate

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    The high cost of energy consumption in buildings highlights the importance of research focused on improving the energy efficiency of building’s envelope systems. It is important to characterize the real behavior of these systems to know the effectiveness in terms of energy reduction. Therefore, the aim of this paper is to characterize the thermal performance of facades based on experimental monitoring of outdoor test cells in tropical climate. To carry out this research, a case study was presented to compare two construction systems. One of them is a light façade (M1) and the other a reference façade (M2). A thermal simulation was performed for the opaque and glazed facades. In addition, several parameters were measured with different types of sensors, as well as environmental variables to evaluate the thermal and lighting behavior of multiple facades systems under real conditions. The findings show that light façade behavior was the opposite of what was expected, since by incorporating a window in the façade it has allowed solar radiation to increase the interior temperature in both modules. In the case of the light facade the penalization was higher than the reference facade, which has a lower thermal transmittance than M1. Doi: 10.28991/cej-2021-03091773 Full Text: PD

    Estimating Potential Evapotranspiration by Missing Temperature Data Reconstruction

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    This work studies the statistical characteristics of potential evapotranspiration calculations and their relevance within the water balance used to determine water availability in hydrological basins. The purpose of this study was as follows: first, to apply a missing data reconstruction scheme in weather stations of the Rio Queretaro basin; second, to reduce the generated uncertainty of temperature data: mean, minimum, and maximum values in the evapotranspiration calculation which has a paramount importance in the manner of obtaining the water balance at any hydrological basin. The reconstruction of missing data was carried out in three steps: (1) application of a 4-parameter sinusoidal type regression to temperature data, (2) linear regression to residuals to obtain a regional behavior, and (3) estimation of missing temperature values for a certain year and during a certain season within the basin under study; estimated and observed temperature values were compared. Finally, using the obtained temperature values, the methods of Hamon, Papadakis, Blaney and Criddle, Thornthwaite, and Hargreaves were employed to calculate potential evapotranspiration that was compared to the real observed values in weather stations. With the results obtained from the application of this procedure, the surface water balance was corrected for the case study

    Biodegradation of lignocellulosics: microbial, chemical, and enzymatic aspects of the fungal attack of lignin

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    Wood is the main renewable material on Earth and is largely used as building material and in paper-pulp manufacturing. This review describes the composition of lignocellulosic materials, the different processes by which fungi are able to alter wood, including decay patterns caused by white, brown, and soft-rot fungi, and fungal staining of wood. The chemical, enzymatic, and molecular aspects of the fungal attack of lignin, which represents the key step in wood decay, are also discussed. Modern analytical techniques to investigate fungal degradation and modification of the lignin polymer are reviewed, as are the different oxidative enzymes (oxidoreductases) involved in lignin degradation. These include laccases, high redox potential ligninolytic peroxidases (lignin peroxidase, manganese peroxidase, and versatile peroxidase), and oxidases. Special emphasis is given to the reactions catalyzed, their synergistic action on lignin, and the structural bases for their unique catalytic properties. Broadening our knowledge of lignocellulose biodegradation processes should contribute to better control of wood-decaying fungi, as well as to the development of new biocatalysts of industrial interest based on these organisms and their enzymes. [Int Microbiol 2005; 8(3):195-204

    Biogeographical patterns in the diet of an opportunistic predator: the red fox Vulpes vulpes in the Iberian Peninsula

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    Biogeographical diversity is central to the trophic ecology of predators. Understanding the biogeographical trophic patterns of generalist predators, such as the red fox Vulpes vulpes, is particularly challenging because of their wide distributions, broad trophic spectra and high ecological plasticity, which often generate conflicts with humans. We reviewed 55 studies from the Iberian Peninsula concerning the diet of the red fox to describe its trophic patterns from a biogeographical perspective. We considered the frequency of occurrence of seven food groups and characterized each study site according to environmental variables. We tested relationships between geographical variables and each food group independently, and assessed the consumption of lagomorphs in relation to the other food groups. We also tested the relationships between trophic diversity, the main food groups, latitude and altitude, and finally investigated changes in the consumption of all food groups in relation to habitat type and seasonality. We found a latitudinal pattern in the diet of the red fox, which was characterized by a greater consumption of lagomorphs and invertebrates in southern areas, and a higher intake of small mammals and fruits/seeds in northern regions. Additionally, the consumption of invertebrates increased from east to west, while fruit/seed consumption increased from west to east. Consumption of lagomorphs decreased, and of small mammals increased, with altitude. Trophic diversity was not associated with geographical variables. The intake of lagomorphs and small mammals was greatest in Mediterranean scrub and forest, respectively. Reptiles and invertebrates were consumed mostly during summer; fruits/seeds in autumn. Iberian red foxes show variation in their feeding habits associated with environmental variables, which are in turn associated with the availability of their main prey. Foxes select rabbits where they are abundant, and feed on small mammals and fruits/seeds where lagomorphs are scarce.M. Delibes-Mateos currently holds a Juande la Cierva research contract awarded by the Ministerio de Ciencia e Innovación and the European Social Fund. C. Ferreira was supported by a PhD grant (Ref. SFRH/BD/22084/2005) funded by the Fundação para a Ciência e Tecnologia of the Ministério da Ciência, Tecnologia e Ensino Superior, Portuguese government. Financial support for the study was provided by the Spanish MICINN Project CGL2009-10741 from Spanish Plan Nacional de I+D and FEDER funds.Peer Reviewe

    Biostimulant Potential of Scenedesmus obliquus Grown in Brewery Wastewater

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    Microalgae are microorganisms with the capacity to contribute to the sustainable and healthy food production, in addition to wastewater treatment. The subject of this work was to determine the potential of Scenedesmus obliquus microalga grown in brewery wastewater to act as a plant biostimulant. The germination index of watercress seeds, as well as the auxin-like activity in mung bean and cucumber, and in the cytokinin-like activity in cucumber bioassays were used to evaluate the biostimulant potential. Several biomass processes were studied, such as centrifugation, ultrasonication and enzymatic hydrolysis, as well as the final concentration of microalgal extracts to determine their influence in the biostimulant activity of the Scenedesmus biomass. The results showed an increase of 40% on the germination index when using the biomass at 0.1 g/L, without any pre-treatment. For auxin-like activity, the best results (up to 60% with respect to control) were obtained at 0.5 g/L of biomass extract, after a combination of cell disruption, enzymatic hydrolysis and centrifugation. For cytokinin-like activity, the best results (up to 187.5% with respect to control) were achieved without cell disruption, after enzymatic hydrolysis and centrifugation at a biomass extract concentration of 2 g/L

    Canopy arthropod declines along a gradient of olive farming intensification

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    Arthropod declines have been linked to agricultural intensification. However, information about the impacts of intensification is still limited for many crops, as is our understanding of the responses of different arthropod taxa and trophic groups, thus hindering the development of effective mitigation measures. We investigated the impacts of olive farming intensification on canopydwelling arthropods in the Mediterranean region. Intensification involves the increased use of agrochemicals, mechanisation and irrigation, but also structural changes from traditional orchards with low densities of large and old trees, to intensive and superintensive orchards with high to very high densities of smaller and younger trees, respectively. Canopy arthropods were vacuumsampled at 53 sites representing the three orchard intensification levels, in spring, summer and autumn 2017. We evaluated how the arthropod community varied across intensification levels, and in response to orchard structure, management and landscape context. We found no changes in the diversity of arthropod taxa across intensification levels after correcting for sample coverage, but arthropod abundance declined markedly along the intensification gradient. Decreased abundance was associated with changes in orchard structure, lower herbaceous cover, and higher herbicide and insecticide use. The abundance of a specialized olive pest was lower in landscapes with higher woodland cover. The negative effects of intensification were stronger in spring and summer than in autumn, and parasitoids and predators were particularly affected. Overall, results suggest that retaining herbaceous cover, reducing agrochemical inputs and preserving natural woody elements in the landscape, may contribute to mitigate impacts of olive farming intensification on canopy arthropods, particularly on beneficial speciesinfo:eu-repo/semantics/publishedVersio

    Canopy arthropod declines along a gradient of olive farming intensification

    Get PDF
    Arthropod declines have been linked to agricultural intensification. However, information about the impacts of intensification is still limited for many crops, as is our understanding of the responses of different arthropod taxa and trophic groups, thus hindering the development of effective mitigation measures. We investigated the impacts of olive farming intensification on canopy-dwelling arthropods in the Mediterranean region. Intensification involves the increased use of agrochemicals, mechanisation and irrigation, but also structural changes from traditional orchards with low densities of large and old trees, to intensive and superintensive orchards with high to very high densities of smaller and younger trees, respectively. Canopy arthropods were vacuum-sampled at 53 sites representing the three orchard intensification levels, in spring, summer and autumn 2017. We evaluated how the arthropod community varied across intensification levels, and in response to orchard structure, management and landscape context. We found no changes in the diversity of arthropod taxa across intensification levels after correcting for sample coverage, but arthropod abundance declined markedly along the intensification gradient. Decreased abundance was associated with changes in orchard structure, lower herbaceous cover, and higher herbicide and insecticide use. The abundance of a specialized olive pest was lower in landscapes with higher woodland cover. The negative effects of intensification were stronger in spring and summer than in autumn, and parasitoids and predators were particularly affected. Overall, results suggest that retaining herbaceous cover, reducing agrochemical inputs and preserving natural woody elements in the landscape, may contribute to mitigate impacts of olive farming intensification on canopy arthropods, particularly on beneficial species

    Lixiviação de glyphosate e imazapyr em solos com diferentes texturas e composição química. I - método do bioensaio

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    A mobilidade dos herbicidas no perfil do solo é influenciada por vários processos, tais como, retenção, transformação e transporte. O conhecimento destes fenômenos é fundamental para a perfeita compreensão do destino de tais produtos no ambiente. Dentre as várias técnicas utilizadas nesses estudos, o método do bioensaio apresenta-se como de ótima representatividade e reprodutibilidade. Em razão dessas características, associadas a poucas informações sobre a mobilidade de herbicidas nos solos sob condições tropicais, foi conduzido um bioensaio objetivando verificar o movimento vertical do glyphosate e do imazapyr, em colunas de solos de diferentes texturas e composição química, utilizando-se o tomateiro (Lycopersicon esculentum Mill var. Santa Clara) como planta-teste. Os resultados desse estudo permitiram concluir que: a) o limite de detecção do bioensaio para o glyphosate e para o imazapyr corresponde ao menor valor de I50, obtido na curva padrão, 331,52 e 5,4 µg L-1, respectivamente; b) as concentrações do glyphosate biologicamente ativo nos lixiviados dos solos de Viçosa e de Sabará encontram-se abaixo do limite de detecção do bioensaio; c) o glyphosate apresentou, na coluna de 1 cm, mobilidade muito baixa nos solos estudados; d) a mobilidade do imazapyr, na coluna de 30 cm, é maior no solo de textura francoarenosa de Viçosa; e) o alto teor de argila e de matéria orgânica do solo de Sabará apresentam-se como os principais fatores de retenção do imazapyr nesse solo.The herbicide mobility in the soil profile is influenced by several processes: retention, transformation and transport. This phenomenon knowledge is essential to the perfect comprehension of these product destines in the environment. Among the several techniques used in such studies, the bioassay method presents optimum representativeness. Because these characteristics and the scarce information about the herbicide mobility in soils under tropical conditions, a bioassay was carried out aiming to verify the vertical movement of glyphosate and imazapyr in soil columns with different textures and chemical composition using the tomato (Lycopersicon esculentum Mill var. Santa Clara) as test-plant. According to the results it may be concluded that: a) the bioassay detection boundary for both the glyphosate and imazapyr corresponds to the lowest I50 value obtained in the pattern curve that is 331.52 and 5.4 µg L-1 respectively; b) the concentrations of the biologically active glyphosate in the leaching products of Viçosa and Sabará soils are bellow the bioassay detection boundary; c) in the 1 cm column, the glyphosate presented a very low mobility in the studied soils; d) in the 30 cm column, the imazapyr mobility is greater in the sandy loam texture soil of Viçosa; e) the high clay and organic matter contents in Sabará soil present as the main retention factors of imazapyr in this soil
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